We studied the accuracy of reported family histories of essential tremor (ET) by questioning the patients in our clinic and subsequently by mail and phone. For individuals who continued to report a negative family history, we mailed a screening questionnaire to their first-degree relatives to further ascertain the presence of ET. On initial assessment, 67.7% of patients reported a positive family history of ET, but following all assessments, 96.0% of patients had a positive family history. We conclude that a negative family history of ET is often inaccurate, and that ET is primarily a hereditary disease.